Randomization as a concept to improve follow-up and reduce cost in long term health related quality of life studies addressing cardiac surgery

Introduction: Long-term assessment of health-related quality of life is challenging especially if designed to include all patients. A weakness of such programs can be response rate, the amount of work and cost. We explore randomization schedules to achieve sufficient information to accurately assess HRQL, reduce follow-up efforts and institutional cost.

Methods: Subjects (n=395) were enrolled in our prospective HRQL program following cardiac surgery. HRQL was assessed using the SF-12 Composite Mental (CMS) and Physical (CPS). Analyses included baseline subgroup identification and explore randomization to maximize information collected and minimize HRQL variance.

Results: Subject. Procedures and subjects were primarily elective (55%), male (77%), aged 64 yrs and former smokers (58%). No significant temporal (am/pm, month, weekday), operative status, or CABG vs. valve differences were observed among either composite physical (CPS) or mental scores (CMS) at baseline or 12-months. Women and more severely diseased pts were significantly different at baseline and 12 months. CMS samples averaged 0.007 (range: -1.93-2.03) from the CMS grand mean (51.71). CPS samples averaged 0.04 (range: -1.70-1.60) from the CPS grand mean (44.19). Patterns of deviations from the grand mean for both CMS and CPS from smallest to largest randomization groups were clearly evident with increasing samples. Using this technique, only in samples Ан 50% were the majority of detected deviations from the grand mean detected < 0.25.

Conclusion: In a homogeneous patient population such as ours, randomization is a feasible option. By randomizing every third patient, the scientific integrity is maintained and is much more cost-effective.